Last April I watched an ancient Russian helicopter landing at a remote dirt airstrip in western Nepal. The chopper had been chartered by the World Food Programme to fly in food to Mugu, the poorest district in Nepal, a country still recovering from a 10-year civil war.

Mugu is a long way from the parts of Nepal familiar to tourists. In fact, it's a long way from anywhere. There are no cosy lodges for trekkers to relax in after a hard day's walking. Most people in Mugu are subsistence farmers. If their growing season is interrupted for whatever reason – like the civil war, or unusual weather events – then people go hungry. That's why the WFP is there.

Except now the WFP isn't there, or at least not to the extent that they were. Funding for the WFP has dried up because of the financial crisis that has convulsed the developed world. Most of us feel resentful about job insecurity caused by reckless lending. For many people in Nepal, the consequences are becoming life threatening.

With a collapse in tax revenues, there isn't the spare cash around to support the WFP's humanitarian relief work, or longer-term schemes to help those who are deemed "food insecure". This has happened at a time of high food prices in a country where the only way to deliver food in large quantities is in the back of an expensive aircraft.

Over the last three years, the number of people WFP helps has almost tripled, from 1.2 million to 3.4 million. The reasons are complex. Long-term investment in agriculture collapsed during Nepal's civil war and has yet to recover. Severe weather has disrupted crops on several occasions in the last four years, arguably as a consequence of climate change. Food prices have rocketed.

But now, because of the collapse in support from western countries, the WFP is facing a crisis. In December, it was only able to provide food for 600,000 of the 1.2 million most needy, those who are most vulnerable to food shortages. Cuts have been made in 15 of the 30 districts where the WFP delivers food.

These are not people who are on the verge of starvation. There won't be pictures of dying children on the television news. But the long-term impacts of malnutrition in a country like Nepal are profound. In the remote hills of Nepal, the rate of chronic malnourishment among children under five reaches 60%. That figure compares to 42% for Somalia or a similar figure for the Democratic Republic of Congo.

It's what the WFP calls "a silent crisis", and in a country still disabled by insecurity and the threat of renewed civil conflict, the extra burden prompted by millions of people going hungry could be critical.

In the longer term, this appalling rate of child malnourishment coupled with a crumbling state education system will cost Nepal dear. Like other countries in the Himalayan region, Nepal faces a future of rising population, severe climate change and political instability, with many of its children literally disabled by malnourishment. It can't be allowed to happen.

The British people rightly felt that Gurkhas who served in the British army should be given the rights they deserved. There is less glamour in helping Nepal sort out its agricultural sector so it can prosper unaided.

But Nepal is a key link in a chain of increasingly weak political entities stretching along the Himalaya, a crucial region buffering India and China. It's in everybody's interests that Nepal prospers.

The WFP need $7m a month to restore its food programme in Nepal. Otherwise the Nepalese farmers I met in April and thousands like them will be forced to sell off livestock and eat seed stocks. That will generate another crisis at even greater cost. The time to act is now.